Biomedical subjects

R Kato

Publications and source records attributed to R Kato.

At least 145 records · Page 8Linked to original sources

PubMed1997

Assignment of the human connexin43 gene, GJA1, to chromosome 6q22.3.

Connexin43 is one of connexin proteins which make up the intercellular gap junctions. Targeted null mutation of the mouse connexin43 gene has been reported to result in a cardiac malformation. Moreover, single-base mutations of the human homolog (GJA1) were identified in patients with laterality defects of the chest and abdominal organs, suggesting that connexin43 contributes to the determination of laterality during organogenesis. We mapped GJA1 to 6q22.3 by fluorescence in situ hybridization, using a bacterial artificial chromosome (BAC) clone that covered almost the entire GJA1-cDNA, as a probe.

Chromosome Mapping↗

PubMed1997

Fish mapping of a translocation breakpoint at 6q21 (or q22) in a patient with heterotaxia.

Heterotaxia is a congenital lateralization defect of visceral organs. As several single-genes that act on the formation of left-right asymmetry during embryogenesis have been identified in animals, a defect in the similar system may play a role in heterotaxia in man. We previously reported a Japanese girl with heterotaxia associated with a de novo balanced translocation (6;18)(q21 or q22;q21.3 or q22). In the present study, based on a hypothesis that one of the putative situs-determining genes is disrupted at a breakpoint of the translocation, we first isolated a yeast artificial chromosome (YAC) clone covering a breakpoint, 6q21 (or q22) of the translocation. Then, using STSs mapped on the YAC, we isolated bacterial artificial chromosome (BAC) clones spanning the breakpoint. FISH analysis using the BAC clones as probes revealed that the breakpoint is confined to a segment between two STS loci, WI-4066 and the CHLC.GATA6B06.192, within a genetic distance of 1.4 cM. The human connexin43 gene was not disrupted in our patient, although mutations of this gene have been reported in patients with complex heart disease and heterotaxia. The molecular localization of the translocation breakpoint in our patient may contribute to the positional cloning of a putative heterotaxia gene.

Blotting, Southern↗

PubMed1997

A randomized study comparing VMCP and MMPP in the treatment of multiple myeloma.

PURPOSE: To compare VMCP, a multidrug combination chemotherapy comprising vincristine (VCR), melphalan (MPH), cyclophosphamide (CPM) and prednisolone (PSL), with MMPP comprising MPH, ranimustine (MCNU), procarbazine, and PSL as induction, to elucidate the value of alternating combination chemotherapy, and to search for an appropriate maintenance therapy in multiple myeloma. METHODS: At 16 institutions in the Nagoya City area, we carried out a randomized trial of VMCP versus MMPP as the initial treatment. Patients who were refractory or resistant to the initial therapy were crossed over into the other arm (crossover trial). For patients who achieved a partial response (PR) or a minor response (MR) and in whom the paraprotein level ceased to decrease, the maintenance therapy was randomized either to an MPH/PSL combination (MP) or to alternating combination therapy (AT) with VMCP and MMPP. RESULTS: In the 94 evaluable patients of the 111 enrolled, the response rate (PR rate) was 27.7% (13/47) in the VMCP arm and 44.7% (21/47) in the MMPP arm (P = 0.0859). The crossover trial resulted in a PR rate of 15.8% (3/19) for the VMCP-->MMPP crossover and 14.3% (2/14) for the MMPP-->VMCP crossover. The median survival time was 23.4 months for those initially begun in the VMCP arm and 24.9 months for those in the MMPP arm, showing a tendency for better survival during a follow-up of 2-6 years with MMPP treatment, but without statistical significance. The survival time of patients with progressive disease was significantly shorter than that of patients with PR, MR or no change (NC). However, there was no significant difference in the survival rate among those who achieved PR, MR, or NC. As to the maintenance therapy, there was no significant difference in survival between MP therapy and AT. Patients who reached a plateau phase survived significantly longer than those who did not. Except for six cases of grade 3 or 4 neurotoxicity in the VMCP arm, there was no significant difference in the hematologic or gastrointestinal toxicity between the two arms. CONCLUSIONS: We conclude that VMCP is less effective for myeloma than MMPP as the induction treatment, that alternating noncrossresistant chemotherapeutic combinations do not offer an advantage in multiple myeloma, and that patients who reach a plateau phase have a significantly longer survival time.

Adult↗

PubMed1997

Molecular mapping of a translocation breakpoint at 14q13 in a patient with mirror-image polydactyly of hands and feet.

Mirror hands and feet (MIM, 135750) is a rare congenital anomaly, and mirror-image polydactyly is considered to be a variant of mirror hands and feet. To our knowledge, seven patients with the disorder have been reported in the literature. Parent-to-child transmission was reported in two families, which may indicate a single-gene defect inherited in an autosomal dominant fashion. We had previously encountered a boy with mirror-image polydactyly whose karyotype showed 46,XY,t(2;14) (p23.3;q13) de novo. We hypothesized that at least one of the putative genes responsible for the determination of an anterior-posterior limb pattern is disrupted by a translocation breakpoint. In this study, we identified a yeast artificial chromosome clone spanning a translocation breakpoint at 14q13, and the breakpoint was confirmed to be located between two loci, AFM200ZH4 and D14S306, within a genetic distance of 0.6 cM.

Chromosome Mapping↗

PubMed1997

Alteration of platelet aggregation in patients with thyroid disorders.

To determine whether Graves' disease or primary hypothyroidism influence platelet function, we evaluated platelet aggregation in the platelet-rich plasma (PRP) from such patients. Platelet aggregation induced by adenosine diphosphate (ADP) in blood obtained from patients with untreated Graves' disease was significantly lower than normal, whereas that in patients with untreated primary hypothyroidism was relatively increased. The magnitude of platelet aggregation induced by collagen in both groups of patients resembled that induced by ADP. However, significant differences were evident between the two diseases (P < .05). In addition, we observed a significant inverse correlation between the extent of platelet aggregation and plasma levels of thyroid hormones (triiodothyronine [T3], thyroxine [T4], and free T3). Platelet aggregation returned to normal when the euthyroid condition was obtained in the patients following administration of antithyroid drugs or thyroid hormone. The findings are consistent with the possibility that thyroid hormones influence platelet aggregation partly via inhibition of myosin light-chain kinase (MLCK).

Adenosine Diphosphate↗

PubMed1997

Flow cytometry analysis of the Fas ligand expression of activated lymph node T-cells.

There is increasing evidence for the role of the Fas/Fas ligand interaction in the immunoregulation of T-cells. We studied the expression of the Fas ligand (FasL) in activated peripheral T-cell in vitro, and its relation to autonomous cell death by flow cytometry. Following the stimulation of lymph node T-cells with anti-CD3 and rIL2, the mRNA level of FasL increased more than four times during the first 2 days over the level before stimulation. The surface expression of FasL was observed on 27% of the population at day 2 after stimulation and increased to approximately 50% at day 3. Kinetic analysis by flow cytometry, however, indicated that all T-blasts transformed during activation did not express FasL. FasL expression became evident simultaneously with the termination of cell expansion. Since cells remained viable (> 90%) at day 3 as judged by trypan blue-exclusion, cell membranes expressing FasL were supposed to be still intact. Concomitantly with FasL-expression, spontaneous DNA fragmentation was observed. These observations support the idea that autonomous Fas/FasL interaction mediates apoptosis in activated peripheral T-cells as demonstrated in T-cell hybridoma or established T-cells.

Animals↗

PubMed1997

Endothelium-dependent and -independent vasoactive actions of a Japanese kampo medicine, Saiko-ka-ryukotsu-borei-to.

Saiko-ka-ryukotsu-borei-to (TJ-12) is a Japanese kampo medicine used clinically for the treatment of hypertension and atherosclerosis. We investigated the effects of TJ-12 on the contraction of rat thoracic aorta induced by norepinephrine, 5-hydroxytryptamine and high potassium. TJ-12 relaxed endothelium-denuded rings, which had been precontracted with 1 microM norepinephrine, in a dose-dependent manner with an IC50 of 50 micrograms/mL. However, in the presence of TJ-12, endothelium-intact rings initially showed enhanced norepinephrine-induced contraction, followed by relaxation. Interestingly, TJ-12 dose-dependently reversed nitric oxide (2 microM)-induced relaxation of norepinephrine-induced precontraction ofendothelium-denuded rings, with an IC50 of 20 micrograms/mL. In serotonin-contracted rings, TJ-12 caused slight, though statistically significant, relaxation only at high doses (> 200 micrograms/mL). In constrat to these receptor-mediated contractions, TJ-12 failed to affect the tension produced by high potassium 40 mM). These results suggest that the antihypertensive effects of TJ-12 could be related to inhibition of norepinephrine-induced vasoconstriction. In addition, our in vitro experiments revealed an inhibitory effect on nitric oxide-induced relaxation.

Analysis of Variance↗

PubMed1997

Characterization of a thermostable DNA photolyase from an extremely thermophilic bacterium, Thermus thermophilus HB27.

The photolyase gene from Thermus thermophilus was cloned and sequenced. The characteristic absorption and fluorescence spectra of the purified T. thermophilus photolyase suggested that the protein has flavin adenine dinucleotide as a chromophore. The second chromophore binding site was not conserved in T. thermophilus photolyase. The purified enzyme showed light-dependent photoreactivation activity in vitro at 35 and 65 degrees C and was stable when subjected to heat and acidic pH.

Amino Acid Sequence↗

PubMed1997

Thyrotropin (TSH) receptor autoantibodies do not appear to bind to the TSH receptor produced in an in vitro transcription/translation system.

An in vitro transcription/translation (TnT) system was used to produce 35S-labeled full-length TSH receptor (TSHR) and TSHR extracellular domain (TSHRex). The interaction of the labeled proteins with TSHR autoantibodies in Graves' sera was then studied using an immunoprecipitation assay. In the assay, 35S-labeled TSHR or TSHRex were incubated with test sera, and any immune complexes formed were precipitated with protein A-Sepharose (in the case of mouse monoclonal antibodies, antimouse IgG-agarose was used). Rabbit antibodies to the TSHR and a mouse monoclonal antibody precipitated as much as 50% of the 35S-labeled TSHR preparations compared with about 2% for normal rabbit serum and 4% for a control monoclonal antibody. However, none of 34 Graves' sera (TSHR autoantibody levels ranging from 14-95% inhibition of [125I]TSH binding) were able specifically to immunoprecipitate 35S-labeled TSHR or TSHRex. These negative findings were confirmed by analysis of the immunoprecipitates on SDS-PAGE followed by autoradiography. Our results indicate that the TnT system is not useful for producing labeled TSHR preparations that can bind TSHR autoantibodies well. This is in contrast to TnT produced 35S-labeled glutamic acid decarboxylase, thyroid peroxidase, and 21-hydroxylase, which react well with their respective autoantibodies. One main difference between these 3 autoantigens and the TSHR is that the receptor is highly glycosylated, and this extensive glycosylation may be of critical importance for correct folding of the receptor. Consequently, the inability of the TnT system to glycosylate proteins could explain in part why TnT-produced 35S-labeled TSHR and TSHRex do not bind TSHR autoantibodies.

Animals↗

PubMed1997

Comparison of resting beta-methyl-iodophenyl pentadecanoic acid (BMIPP) and thallium-201 tomography using quantitative polar maps in patients with unstable angina.

We compared resting beta-methyl-iodophenyl pentadecanoic acid (BMIPP) tomography with resting thallium-201 tomography in 28 patients with unstable angina. Tracer distribution was displayed on a polar map and compared with a normal standard deviation map obtained from a group of 12 normal subjects. The extent scores and severity scores obtained by BMIPP were significantly greater than those obtained by thallium-201. Confirmation by coronary angiography revealed the sensitivity of the methods in identifying patients to be 89% for BMIPP and 54% for thallium-201. There were significant differences between BMIPP and thallium-201 in the sensitivities of detecting postischemic jeopardized myocardium in the area supplied by the right coronary artery (RCA; 53% vs 18%, p < 0.05), left circumflex artery (LCX; 78% vs 39%, p < 0.025) and all 3 vessels combined (71% vs 35%, p < 0.001) but no significant differences in specificity (RCA: 82% vs 64%; LCX: 70% vs 90%; and total 3 vessels combined: 75% vs 79%). In conclusion, resting BMIPP tomography is more sensitive than resting thallium-201 tomography in detecting postischemic myocardial damage in patients with unstable angina.

Angina, Unstable↗

PubMed1997

Activation of phorbol ester responsive form of protein kinase C zeta in association with Ca(2+)-induced differentiation of primary cultured mouse epidermal cells.

In primary cultured mouse epidermal cells, protein kinase C (PKC) zeta consists of multiple forms: a low salt-eluted PKC zeta (1-PKC zeta, 79 and 85 kDa) and a high salt-eluted PKC zeta (h-PKC zeta, 79 and 85 kDa) by anion-exchange column chromatography (K. Nishikawa et al., Cell. Signal. 7, 491-504, 1995). In the present study, PKC isozyme-specific responses during terminal differentiation of epidermal cells, which were induced by the increase of Ca(2+)-concentration in culture medium, were examined. After 24 hr-treatment with 1.8 mM Ca2+, 79-kDa 1-PKC zeta in the particulate fraction was apparently shifted to the 85-kDa form. The phosphatidylserine-dependent kinase activity of this 1-PKC zeta was increased in association with the shift. These results suggest the pivotal role of 1-PKC zeta in the particulate fraction in the Ca(2+)-induced epidermal cell differentiation processes.

Amino Acid Sequence↗

PubMed1997

Relation between stable glycated hemoglobin A1C and plasma glucose levels in diabetes-model mice.

In an IDDM model mouse which was inoculated with a diabetogenic variant, DK-27, of encephalomyocarditis (EMC) virus, the relation between a stable glycated hemoglobin A1C (St-HbA1C) level and plasma glucose level (PGL) in the progress of diabetes was studied. The St-HbA1C level and PGL were examined every 2 weeks for 10 weeks in normal male DBA/2 and IDDM-onset mice. PGLs of normal control mice did not change, but their St-HbA1C levels were slightly increased by 0.52 to 1.03%. On the other hand, in IDDM mice, their PGLs were greatly increased (> 400 mg/dl) and hyperglycemia was maintained throughout this observation period, with their St-HbA1C noticeably increased to 3.8% according to the progress of diabetes for 10 weeks. A highly significant correlation between St-HbA1C levels and averaged PGLs for the past weeks was found in IDDM mice. To examine the reflection of St-HbA1C levels to delicately varied PGLs, we also estimated both values in IDDM mice which were treated with insulin at a minimal effective dose once a day for 4 weeks. The St-HbA1C levels in insulin-injected IDDM mice were significantly lower than those in control IDDM mice. These findings suggest that the estimation of the St-HbA1C level is useful in following up blood glucose control in a long-term therapeutical study with small laboratory animals.

Animals↗

PubMed1997

[Long-term clinical course of Peyronie's disease treated conservatively].

BACKGROUND: To evaluate the natural history of Peyronie's disease and to determine the suitable time for surgical treatment, we investigated changes of clinical findings of the disease over time. PATIENTS AND METHODS: We evaluated changes of plaque size, penile curvature and erectile dysfunction in 10 patients with Peyronie's disease. The mean follow-up period was 36.8 months. RESULTS: At the first examination, the mean plaque size of patients with erectile dysfunction was larger than that of those without erectile dysfunction, suggesting a positive association between size and erectile function. There was no significant relationship between plaque size and penile pain or penile curvature. The mean size of plaques decreased significantly compared with that at the first examination (p < 0.05). However, penile curvature, pain and erectile dysfunction persisted during the follow-up period in all but one patient, who showed improvement of penile curvature. CONCLUSION: These results suggest that we may recommend a shorter observation period until surgery that we have done for some patients who want to be surgically treated.

Adult↗

PubMed1997

[The studies of extracorporeal shock wave lithotripsy (ESWL) for pancreatic ductal stones].

30 patients with main pancreatic duct stones were treated by ESWL. In 18 of 22 patients who had not previously undergone endoscopic pancreatic sphincterotomy (EPST) or endoscopic sphincterotomy (EST), the stone fragments disappeared after ESWL. The fragments were removed endoscopically in the remaining 4 cases. Complete clearance was achieved in 8 cases with endoscopically unextractable stones by ESWL. After the ESWL procedure, absolute relief from pain was reported by in 19 of 22 patients with abdominal complaints. Serum amylase levels decreased significantly, and dilatation of the main pancreatic duct (MPD) was reduced. In the medium-term follow-up period, pancreatic exocrine function and endocrine function had a possibility to be preserved. One case of pancreatic cancer and one case of an intraductal papillary tumor of the pancreas were found, indicating that careful observation is necessary even after complete removal of pancreatic stones. In cases of Santorini duct dominant, multiple stones, or stricture of the MPD, ESWL should be combined with EPST and endoscopic stenting for preventing recurrence of acute pancreatitis and pancreatic stones. In conclusion, ESWL is the first choice of treatment for pancreatolithiasis and useful procedure and the limited complications.

Adult↗

PubMed1997

Thoracic duct cyst in supraclavicular region.

A 28-year-old female attended an outpatient clinic in October, 1989, because of a tumor in the left supraclavicular fossa, detected in a health examination. Following exploratory puncture of the tumor which yielded milky-white fluid, suggesting a cyst in the thoracic duct, she was admitted to our department. The cyst was unilocular measuring about 6 cm in diameter, and the fluid content was chyle-rich in lipids. Lymphography demonstrated a lymphatic structure adjacent to the lesion and scattered lymph vessels on the cyst surface. On November 16 the cyst was resected. A restiform structure was observed between the cyst and the thoracic duct, but the presence or absence of communication was unclear. The histological diagnosis was thoracic duct cyst. Thoracic duct cyst occurring in the cervical region is very rare. Our case may provide useful information as to its pathogenesis and the mode of retention of cyst fluid.

Adult↗

PubMed1997

Depressed mechanoenergetics and compensatory responses in idiopathic dilated cardiomyopathy.

The aim of this study was to clarify that the depressed mechanoenergetics in patients with idiopathic dilated cardiomyopathy (DCM) resulted from compensation for the decreased contractility. The study population consisted of eight control subjects, with normal left ventricular size and ejection fraction and 31 patients with DCM. Left ventricular end-systolic elastance (Ees), effective arterial elastance (Ea), external work (EW), and the pressure-volume area (PVA) were measured, using a dual-field volume conductance catheter equipped with a micromanometer-tipped catheter. Ea/Ees was evaluated as ventriculoarterial coupling. Normal hearts worked at almost optimal condition (defined as Ea/Ees = 1/2), while ventriculoarterial coupling was far from the optimum (Ea > Ees) in patients with DCM. Ees in patients with DCM was less than that in control subjects; however, Ea was similar in the two groups. The mismatch of Ea/Ees observed in DCM leads to depressed mechanoenergetics as a result of the compensatory response to maintain adequate blood pressure. Volume enlargement plays an important role in maintaining adequate blood pressure and cardiac output in the course of chronic deterioration of contractility.

Blood Pressure↗

PubMed1996

Glutamic acid decarboxylase autoantibody assay using 125I-labelled recombinant GAD65 produced in yeast.

We describe a new method for measuring autoantibodies (Ab) to the 65 kDa isoform of glutamic acid carboxylase (GAD65). In particular, GAD65 without the hydrophobic N-terminal region has been produced in yeast, purified, labelled with 125I and reacted with GAD65 Ab. Antibody bound 125I-GAD65 is then precipitated by the addition of solid phase protein A. With the assay, GAD65 Ab were detected in 59 of 71 (83%) islet cell antibody (ICA) positive IDDM patients and in 8 of 23 (35%) ICA negative IDDM patients (overall 67 of 94 (71%) of IDDM patients). Low concentrations of GAD65 Ab were also detected in 2/98 (2%) healthy blood donors and 1/27 (4%) Graves' disease patients had a high level of antibody. GAD65 Ab were not detected in any of 10 Hashimoto's thyroiditis, 20 Addison's disease or 19 myasthenia gravis sera. There was good agreement between the 125I assay and the current reference method based on 35S-labelled full-length GAD65 (produced by in vitro transcription/translation reaction) and solid phase protein A (r = 0.91, n = 108). Overall, our 125I assay showed sensitivity, precision and disease group specificity at least as good as any assay so far described. These features, combined with a simple assay protocol and the convenience of 125I counting and handling indicate that the method is suitable for routine GAD65 Ab measurements.

Adult↗

PubMed1996

De novo balanced translocation (6;18)(q21;q21.3 or q22) [corrected] in a patient with heterotaxia.

We report on a sporadic case of heterotaxia with a de novo chromosome structural abnormality. The patient had inversely located heart (dextrocardia), stomach, duodenum, and cecum. In addition, she had cerebral atrophy, hypertelorism with telecanthus, infraorbital skin furrows, ear-lobe grooves, prominent maxilla and teeth, large carp mouth, short fifth fingers with limited flexion, generalized hypotonicity, and severe psychomotor retardation. High-resolution chromosome banding analysis demonstrated an apparently balanced translocation: 46,XX,t(6;18)(q21;q21.3). It is hypothesized that both heterotaxia and the chromosomal abnormality in the patient are causally related and a putative situs determining gene has been disrupted by the chromosome break, i.e., a position effect or a cryptic deletion at around the breakpoints. The translocation in our patient may be a good source for positional cloning of the gene.

Abnormalities, Multiple↗